2 ms·

> And an arc minute's area, viewed from low orbit, is somewhat bigger than a football field. This means if you take a point light designed to light a football

> And an arc minute's area, viewed from low orbit, is somewhat bigger than a football field. This means if you take a point light designed to light a football field (football fields do have these light sources), and direct it into space instead of the ground, will be visible from low orbit. > Much more difficult and impressive. People did it with less powerful light sources: https://www.universetoday.com/93987/amateur-astronomers-flash-the-space-station/ https://www.universetoday.com/93987/amateur-astronomers-flas...

Dylan16807 6y ago
> This means if you take a point light designed to light a football field (football fields do have these light sources), and direct it into space instead of the ground, will be visible from low orbit. A point light designed to light up an entire football field should work, yes. What football field has single lights that powerful? Normally you have many flood arrays with a dozen or more lights each. > People did it with less powerful light sources: Cool! So that's somewhere around one kilowatt, significantly easier to do. Though notably it's still a spotlight. I wonder how many watts of flood light you would need.
- Const-me 6y ago
  > Normally you have many flood arrays with a dozen or more lights each. I was thinking about a single array, from the orbit it’s pretty close to a point source. > I wonder how many watts of flood light you would need. I don’t know about efficiency of that military equipment (need beam angle to compute), but I would expect with modern white LEDs you don’t need that many watts, they’re very efficient at converting electricity to light. You would probably still want liquid cooling for them, though.
  - Dylan16807 6y ago
    > I was thinking about a single array, from the orbit it’s pretty close to a point source. It is, but I'm way less impressed when someone says their 4x6 block of floodlights is visible from space, compared to their single light.

Dylan16807 6y ago

> This means if you take a point light designed to light a football field (football fields do have these light sources), and direct it into space instead of the ground, will be visible from low orbit. A point light designed to light up an entire football field should work, yes. What football field has single lights that powerful? Normally you have many flood arrays with a dozen or more lights each. > People did it with less powerful light sources: Cool! So that's somewhere around one kilowatt, significantly easier to do. Though notably it's still a spotlight. I wonder how many watts of flood light you would need.

Const-me 6y ago
> Normally you have many flood arrays with a dozen or more lights each. I was thinking about a single array, from the orbit it’s pretty close to a point source. > I wonder how many watts of flood light you would need. I don’t know about efficiency of that military equipment (need beam angle to compute), but I would expect with modern white LEDs you don’t need that many watts, they’re very efficient at converting electricity to light. You would probably still want liquid cooling for them, though.
- Dylan16807 6y ago
  > I was thinking about a single array, from the orbit it’s pretty close to a point source. It is, but I'm way less impressed when someone says their 4x6 block of floodlights is visible from space, compared to their single light.